We demonstrate that a broadband coherent anti-Stokes Raman scattering (CARS) spectrum generated with a typical two-pulse scheme contains two distinct, significant signals: “2-color” CARS, where the pump and probe are provided by a narrowband pulse and the continuum pulse constitutes the Stokes light, and “3-color” CARS, where the pump and Stokes are provided by two different frequency components in the continuum pulse and the narrowband pulse serves as the probe. The CARS spectra from the two different mechanisms show distinct characteristics in Raman shift range, laser power dependence, and chirping dependence. We discuss the potential for a 3-color CARS signal to cover the fingerprint region with reduced photodamage of live cells. Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States.
© 2007 U.S. Public Domain
Original Manuscript: September 10, 2007
Revised Manuscript: October 19, 2007
Manuscript Accepted: October 25, 2007
Published: November 14, 2007
Vol. 2, Iss. 12 Virtual Journal for Biomedical Optics
Young Jong Lee, Yuexin Liu, and Marcus T. Cicerone, "Characterization of three-color CARS in a two-pulse broadband CARS spectrum," Opt. Lett. 32, 3370-3372 (2007)